setMigrationPluginManager example

  public function testRequirementsForMigrations() {
    $migration = new TestMigration();

    // Setup source and destination plugins without any requirements.     $source_plugin = $this->createMock('Drupal\migrate\Plugin\MigrateSourceInterface');
    $destination_plugin = $this->createMock('Drupal\migrate\Plugin\MigrateDestinationInterface');
    $migration->setSourcePlugin($source_plugin);
    $migration->setDestinationPlugin($destination_plugin);

    $plugin_manager = $this->createMock('Drupal\migrate\Plugin\MigrationPluginManagerInterface');
    $migration->setMigrationPluginManager($plugin_manager);

    // We setup the requirements that test_a doesn't exist and test_c is not     // completed yet.     $migration->setRequirements(['test_a', 'test_b', 'test_c', 'test_d']);

    $migration_b = $this->createMock(MigrationInterface::class);
    $migration_c = $this->createMock(MigrationInterface::class);
    $migration_d = $this->createMock(MigrationInterface::class);

    $migration_b->expects($this->once())
      ->method('allRowsProcessed')